What that means is that when the chamber is loaded and the hammer is forward, the first shot is fired double action. The slide cocks the hammer and the rest of the shots are single action, until you lower the hammer again.

The confusion comes in from modern retards who think Glocks, XDs and other striker fired guns are double action onlys, when in fact they are actually single actions.

The Glock is half cocked and unlocked. The XD is fully cocked. Both are in reality single actions, not double actions only, as the firing pin is COCKED and not at rest, when the chamber is loaded.

WHich is why the new tactical tupperware half cocked and unlocked guns lead the way in accidental discharges, compared to "traditional" single actions like the Beretta/Taurus 92s, the, the Ruger P-85s and the Sig P-226s.

I think the traditional double action style lockwork was first financially successful in the Walther PPK and P-38 pistols.
S&W thought it was the wave of the future when they came out with their model 39 pistol in the 50s. However it didn't really catch on until the 70s and 80s.